Starting with the battery seemed like a good idea. Although the old one was still putting out a good amount of charge, I figured since I was ripping everything out I may as well get the module board out too. I unplugged the numerous amount of cables, got the board out, and swapped out the battery. No sweat.
The next order of business was getting the panel board out from under the top of the synth to deal with all the things that needed addressing there. Out came the many cables running into the panel board, off popped the slider caps, and out slid the board from its slot under the panel. I pulled out the bender assembly as well, as that was going to need its sliders refurbished along with the main array up top.
I looked at the mess of cables I made and suddenly wished I had documented it all better. This would come back to bite me in the ass later.
Next, I desoldered all the faders from the panel board and bender board, and left them to soak in isopropyl alcohol overnight. I bought a glass jar with a screw-on lid for just this purpose. I suppose plastic wrap and a rubber band might have been good enough, but I didn’t want to wake up dead from asphyxiation. No garage or even separate room in my Tokyo rabbit hutch. Getting the hardened dust cover foam sheet off the faders was a little tricky, but I used a hobby knife to slice sideways and managed to not make too much of a mess. Whatever was left sticking to the sliders would get removed in the alcohol bath.
With the faders removed I could now concentrate on changing the tact switches. Nothing too unusual here. I just desoldered all the old ones, popped them out, and soldered in the new ones. What with all the faders and switches in this thing, I really wished I had a desoldering gun or something like that. I’m pretty good with the braid but it takes a long time, but sometimes the solder just doesn’t want to come up. I’m OK at the manual vacuum pump but I still need to work on my angle. I also occasionally burn the board or lift a solder pad and that’s really annoying. Maybe someday I’ll spring for a desoldering gun.
Back to the Juno, it was now time to take apart the faders for a good cleaning. As I learned from my RS-09, orientation of faders is important. I was very careful to keep everything oriented the same way, using the tabs on the bottom as landmarks. I used a tiny precision screwdriver to pry open the tabs, carefully removed the track, cleaned out the inside of the housing and the top of the track with a cotton swab, sprayed a little DeOxit Fader Lube on the track, and then coated the inside of the housing with DeOxit Fader Grease. I also made sure that there was nothing sticking to the tiny, delicate arms that reach down from the bottom of the moving “car” part that connects with the track. I put it all back together, again mindful of the orientation, and used the screwdriver to push the tabs back down, no small feat considering how lubed up and slippery everything was.
With all the faders reassembled and moving lickety split, I soldered them back in. During all the painstaking work that this procedure required, I kept kicking myself for not just leaving them alone. It’s not like they didn’t work. They were just a little stiff. But now that they’re done I’m so happy I did the work. They’re so smooth now and just a joy to use.
But I’m getting ahead of myself. There was a little more pain to experience before the joy. I plugged all the boards back in, turned it on, and nothing. Not even LEDs or numbers. It was at this point that I wished I had taken pictures of the cabling. After trying different combinations of cables and plugs, and looking at pictures online, I finally got it sorted. Later it occurred to me I could have used the service manual to do this as well. But all’s well that ends well.
But of course it wasn’t over yet. The HPF switch was completely dead and the bender board was doing really weird things. Cool, odd bendy things but not typical Juno things. First, the high-pass filter. I took it apart again and checked it with a multimeter. I was definitely getting readings at all the notch points. My issue was the little arm that connected with the track had gotten bent in reassembly and wasn’t making contact. I gently worked it back into place and put it back together. Success. Remember that the HPF switch has two tracks and two arms but only one is actually used.
It wasn’t time to celebrate yet as there was still more work to do. As you might remember from my Yamaha SK20 restoration, I had some acrylic felt leftover and planned to use that to make fader dust covers, but I read online that they can shed over time so I tried foam instead. Taking a direct tip from the guy currently restoring a Jupiter-8, I bought a sheet of 1mm black EVA foam off eBay. I did my best to cut out sheets of it. Laser-cut would be best but I don’t have a laser gun (haha, joke) so I used scissors. It looks like junk but it works.
With everything back together, I loaded in the factory presets from this site. I almost freaked when I got to bank B and found it empty but then realized that the banks have to be loaded separately.
Looking back, it was a lot of work to restore this Juno-106. Was it worth it? Yes, by all means. It’s such a joy to play now. In fact, I’ve been ignoring my other synths because I just can’t get enough of it. I even did this cover of “Comfortably Numb,” mainly with the 106.
I also have a huge sense of satisfaction at having finished this restoration. I accomplished a lot. I failed a few times, but I learned from my mistakes and never gave up. That’s success in my book.